Constant Voltage Regulator (Cvr); Cj Vehicles; Ammeter; Voltmeter - Jeep J-10 Series 1982 Technical & Service Manual

1L-2 ENGINE INSTRUMENTATION
BRAKE
WARNING
INDICATOR FUEL
LAMP GAUGE
LEFT
TURN
FASTEN TEMPERATURE
BELTS GAUGE
WARNING
INDICATOR HIGH BEAM
LAMP
OIL EMERGENCY
PRESSURE DRIVE INDICATOR
„.~U,.GAUGE LAMP (QUADRA -
.KSSw \TBACONLY,
4-WHEEL DRIVE
INDICATOR LAMP
(MODEL 208 TRANSFER
CASE ONLY)
80318
Rg. 1L-2 Cherokee-Wagoneer-Truck Instrumentation
OPERATION
Ammeter
Ammeters are standard equipment for Cherokee,
Wagoneer and Truck vehicles. They are not available for
CJ vehicles.
An ammeter is an instrument used to indicate current
flow into or out of the battery. Whenever the electrical
load caused by the vehicle electrical devices is greater
than the alternator can supply, current flows from the
battery, and the ammeter indicates a discharge (-).
Whenever alternator output is greater than the elec
trical load, the excess current is available to charge the
battery, and the ammeter indicates a charge (+). If the
battery is fully charged, the integral voltage regulator
reduces alternator output to supply only enbugh for the
vehicle electrical load. When this occurs, the ammeter
indicates no charge.
The ammeter is connected in series between the bat
tery and the alternator to indicate the current flow into
and out of the battery.
Voltmeter
A voltmeter is standard equipment for CJ vehicles
only and is not available for other Jeep vehicles. The
voltmeter indicates alternator output voltage. This pro
vides an indication of the charging system's ability to
maintain the battery in a charged condition. Continuous
voltage indications in either the high or low red bands
signify either improper regulation, a broken or slipping
alternator drive belt, shorted alternator diode(s) or a
defective battery. Low voltage indications in the green
band are normal at idle or after prolonged engine starter
motor operation. Continuous voltage indications in the
low green band with the engine above idle speed signify
faulty alternator operation.
Constant Voltage Regulator (CVR)
Several vehicle gauges are designed to operate on low
voltage. The constant voltage regulator (CVR) provides
approximately 5 volts for this purpose. Battery voltage
is supplied to the CVR. The CVR contains a small heat
ing coil and thermostatically operated points. With bat
tery voltage applied to the CVR, the points vibrate at a
rate that produces an average of 5 volts for the gauges.
The CVR is an integral part of the fuel gauge for CJ
vehicles and the coolant temperature gauge for Chero
kee, Wagoneer and Truck vehicles. An external circuit is
used to apply the CVR voltage to the other gauges.
Fuel Gauge
Fuel gauges for all vehicles operate on regulated volt
age provided by the constant voltage regulator (CVR).
The fuel gauge system consists of a gauge, a variable-
resistance sending unit located in the fuel tank, appro
priate wiring and the CVR.
The gauge pointer is attached to a bimetallic coil that
responds to temperature changes. A heating coil
wrapped around the bimetallic coil provides heat that
causes the bimetal to expand. Current flows from the
sending unit in the fuel tank through the heating coil to
the CVR (8 +). The sending unit has high resistance at
low fuel level and very low resistance at high fuel level.
Oil Pressure Gauge
An oil pressure gauge is standard equipment for all
Jeep vehicles.
CJ Vehicles
The oil pressure gauge system consists of an electro
magnetic-type gauge, a variable-resistance sending unit
and appropriate wiring. Battery voltage is applied to the
two coils in the gauge. One coil is connected directly to
ground. The other coil is connected to the sending unit.
The variable resistance in the sending unit is controlled
by the oil pressure. Electromagnetic fields expand
around both coils in the gauge. The pointer is influenced
greater by the coil having the most current flow and the
resulting more intense electromagnetic field.
Cherokee-Wagoneer-Truck
The oil pressure gauge system consists of a gauge, a
variable-resistance sending unit, appropriate wiring and
the constant voltage regulator (CVR). The gauge pointer
is attached to a bimetallic strip that reacts to temper
ature changes. A heating coil wrapped around the bime
tallic coil provides heat that causes the bimetal to